At a Meeting of the Council of the R. Society. January 21. 1674/ 5. Ordered, THAT a Discourse made before the R. Society, Decemb. 10. 1674. by Dr. Nehemiah Grew, Concerning the Nature, Causes, and Power of Mixture, etc. be Printed by the Printer of the R. Society.  
Brouncker. P.R.S.   

A DISCOURSE Made before the ROYAL SOCIETY, Decemb. 10. 1674. Concerning the Nature, Causes, and Power of MIXTURE.  
By Nehemiah Grew, M. D. and Fellow of the R. Society.  
LONDON, Printed for John Martin Printer to the Royal Society, and are to be Sold at the Bell in St. Paul's Churchyard, 1675.   

To the Right Honourable WILLIAM Lord Viscount BROUNCKER, PRECEDENT of the ROYAL SOCIETY.  
My Lord,  
ONE Reason why I dedicate the following Discourse to Your Lordship, is because by Your great and undeserved respects, You have obliged me to do no less. How much more I cannot say, unless I were able to compute the value of Your obligation.  
Another Reason, my Lord, is because I could not but publicly return Your Lordship thanks, for minding the Royal Society of so good a way, as they are lately resolved upon, for the management of a great part of their business. Wherein, my Lord, I do more than presume, that I also speak the sense of the whole Society; I think, not any one excepted.  
I may with the same confidence intimate, my Lord, how happy they account themselves, in having a Person so fit to preside their Affairs, as Your Lordship. The largeness of Your Knowledge, the exactness of Your Judgement, the evenness of Your Comport; being some of those necessary Qualifications, which His Majesty had in His eye, (as right well understanding what He did) when He fixed His choice upon Your Lordship.  
I know, my Lord, that there are some men, who have just so much understanding, as only to teach them how to be ambitious: the flattering of whom, is somewhat like the tickling of Children, till they fall a dancing. But I also know, that Your Lordship unconcerneth yourself as much, in what I even now spoke; as Caesar did himself, when his Soldiers began to style him King. For as he said, Non Rex, sed Caesar: so let Your Lordship be but once named, and all that follows, is but a Tautology to what You are already known to be. Your being Precedent of the Royal Society, Your being the first that was chosen, and chosen by so Wise a King; amounteth to so high and real a Panegyric to Your Lordship, as maketh verbal ones to be superfluous, and leaves them without any sound.  
Whence, my Lord, I have a third Reason most naturally emergent; which is, that I dare to submit myself, as to what I have hereafter said, to Your Lordship's Censure. You being so able, and just an Arbiter, betwixt the same and all those persons therein concerned; that You can neither be deceived, nor corrupted, to make a Judgement in any Point, to the injury of either.  
And truly, my Lord, were it only from a principle of self-interest, yet I could not desire it should be otherwise. For the World, if it lives, will certainly grow as much wiser than it is; as it is now wiser than it was heretofore. So that we have as little reason, to despise Antiquity; as we can have willingness, that we ourselves should be despised by Posterity.  
Yet some difference there is to be made; viz. betwixt those of all Ages, who have been modestly ignorant; and those who have thought, or pretended, that they were Omniscient. Or if knowing and acknowledging that they were ignorant; have yet not been contented to be so; unless, with as good manners, as sense, they did conjure all Mankind, not to offer at the knowing any more than themselves.  
Upon the whole, my Lord, I desire not You should be a Patron, any further than You are a Judge. For if this small Essay hath deserved the least acceptance, I am sure, that in being one, You will be both. Whereby, my Lord, You will not a little nourish and inspire my future endeavours of the like nature: being very solicitous to approve myself,  
My Lord, Your Lordship's most faithful and obedient Servant, Nehemiah Grew.   

A DISCOURSE Made before the ROYAL SOCIETY.  
HAVING the honour to perform the task of this day; I shall endeavour to conform to the Philosophy, which this Society doth profess; which is, Ratiocination, grounded upon Experiment, and the Common Notions of Sense. The former being, without the latter, too subtle and intangible; the latter, without the former, too gross and unmanageable: but both together, bearing a true analogy to ourselves; who are neither Angels, nor mere Animals, but Men.  
The Subject I have chosen to speak of, is Mixture. Whereof, that our Discourse may be the more consistent, and the better intelligible; all I have to say, shall be ranged into this Method; viz.  
1. First, I shall give a brief account of the received Doctrine of Mixture.  
2: Next, lay down some Propositions of the Principles whereof all Mixed Bodies consist.  
3. Then, open the true Nature of Mixture; or say, What it is.  
4. And then enumerate the Causes of Mixture; or say, How it is made.  
5. Lastly, I shall show the Power of Mixture; or, What it can do.  

SECT. I.  
FIRST, As to the received Doctrine of Mixture; not to trouble you with tedious quotations of what Aristotle, Galen, Fernelius, Scaliger, Sennertus, Riverius, and others say hereof; we may suppose the whole summed up in that Definition which Aristotle himself hath given of it, and which the greater number of his Followers, have almost religiously adhered to; viz. that 'tis, 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 Lib. 1. de Gener. & Corrupt. Cap. ult. that 'tis, Miscibilium alteratorum unio. Which Definition, as it is usually explicated, is both unintelligible, and Unuseful.  
Two things are unintelligible; what they mean by Alteration; and what by Union. In this Alteration, they say, That the very Forms of the Elements are altered. And therefore lay it down for an Axiom, Quòd in Mixto, Formae Elementares tantum sint in potentia. But let us see the consequence. For if in a mixed body, the Forms of the Elements are but in potentia; then the Elements themselves are but in potentia: for we all say, Forma dat esse. And if the Compounding Elements, are only in potentia; then the Compound; Body itself can be only in potentia: yet to say it is no more, is most absurd.  
As for the Union of Elements in a mixed Body; they make it such, as brings them at last to assert, the Penetration of bodies, and that the Union of mixed bodies is nothing else. For they say, it is made in such sort, that every particle of the mixed body, partaketh of the Nature of the whole. Which Nature, ariseth from the contemperated Qualities of the four Elements. Whence they conclude, That every particle of the mixed body, containeth in itself all the four Elements. Which is plainly to assert a penetration of bodies. For every Element is, at least, one particle; if therefore every particle of the mixed body, containeth four Elements; then four particles, are but one. I conclude then, That the received Doctrine of Mixture, is unintelligible.  
Whence it follows, That it is also Barren and Unuseful. For who can make any use of that which he understandeth not? And the experience of so many years, wherein it hath been ventilated by the disputes of men, proveth as much: Scarce any of them, except the Learned Sennertus, daring to venture upon Experiment, for fear they should come to understand themselves.  
It is confessed, that many gallant things have been found out by artificial Mixture. But no thanks to this Definition of it. For as an Ignorant Person may make bad Work, and a good Rule be never the worse; so an Ingenious Person may make good Work, and a bad Rule be never the better. The question is not, what have men done? but what have they done upon this foundation, Quòd Mixtio sit miscibilium alteratorum unio. Had this ever taught them to do any thing, even so much as to make the Ink wherewith they have wrote all their Disputes; I confess, they would have had something to show for it. But the truth is, their notions of Mixture, have been so far from doing us any good, that they have done us much harm: being, through their seeming subtlety, but real absurdity, as so many fantastic Spectrums, serving only to affright men from coming near them, or the Subject whereof they treat.  
I shall therefore endeavour to open the true Nature of Mixture. And I shall build my Doctrine upon the Common Notions of Sense: which none can deny; and every one may conceive of. In order to which, I shall take leave to lay down some Propositions, of the Principles of all mixed bodies.   

SECT. II.  
1. AND first, by Principles, I mean Atoms, or certain sorts of Atoms, or of the simplest of Bodies. For otherwise they would not be Principles; for a compounded Principle, in strict speaking, is a contradiction. Even as five, three, or two, are not the Principles of Number, but Unites.  
2. Whence, secondly, it follows, that they are also Indivisible. Not Mathematically; for the Atoms of every Principle have their dimensions. But Physically; and so, what is but one, cannot be made two.  
If it be asked, Whether a Stick cut with a Knife, be not of one, made two? I say, that a Stick, is not one body, but many millions of bodies; that is, of Atoms; not any one whereof is divided within itself, but only they are separated each from other, where the Knife forceth its way. As in the drawing of a man's Finger through an heap of Corn; there is no division made in any one Grain, but only a separation of them one from another, all remaining still in themselves entire. I say therefore, that what is physically one, is also most firm, and indivisible; that is, impenetrable: for penetration is but the separation, not the division of Atoms.  
3. Hence, thirdly, they are also Immutable. For that which cannot be divided, cannot be changed. So that of the whole World of Atoms, not any one hath ever suffered, or can suffer the least mutation.  
Hereupon is grounded the Constancy of Causes and Effects. So that, in all Generations, it is not less certain, that the self same Principle is still propagated from the same; than, that Man is from Man. Wherefore, Compounded bodies are generated; but Principles are not, but only propagated; that is, in every Generation, they pass, in themselves unaltered, from one body, into another.  
4. If Principles, or Atoms are all Immutable; it again follows, That they are of divers kinds. For one and the same Principle, or kind of Atoms, will still make the same thing, and have the same effect: so that all Generations would then be the same. Wherefore, since they are Immutable, they must be divers.  
5. This diversity, for the same reason, is not small, but very numerous. For as the World, taken together, is Nature's Shop; so the Principles of Things, are her Tools, and her Materials. Wherefore, as it speaks the goodness of a Shop; so the perfection of the Universe, That it is furnished with many Tools wherewith, and many Materials whereupon to work. And consequently, that Philosophy beareth best it's own name; which doth not strain all to two or three Principles, like two or three Bells in a Steeple, making a pitiful Chime: but trieth to rise up to Natures own number, and so to ring all the changes in the world.  
6. Yet doth not this vast Diversity, take away the Regiment and Subordination, of Principles. There being a certain lesser number of them, which either by their greater quantity, or other ways, have Rule and Dominion, in their several Orders, over all the rest. For wherever the Subject is Multitude, Order is part of its Perfection. For Order is Proportion. And how can Nature be imagined to hold Proportion in all things else, and not here? Wherefore, as certainly, as Order and Government are in all the parts of the Rational; so certainly, of the Material World.  
Whence it is, That although the Species of Principles be very numerous; yet the Principles called Galenical, Chemical, or any others, which do any way fall under the notice of Sense, are notwithstanding reduceable to a smaller number: viz. according to the number of Predominant Principles in Nature; or, at least, in this part of the Universe which is near and round about us. To the Power and Empire whereof, all other Principles do submit. Which Submission, is not the quitting of their own Nature; but only their appearance under the external Face or Habit of the said Predominant Principles.  
7. As there can be no Order of Principles, without Diversity; so no Diversity, but what is originally made by these two ways; sc. by Size and Figure. By these they may be exceeding different: and all other Properties besides, whereby they differ, must be dependent upon these two.  
8. Nor therefore, can they be of any other Figures, than what are Regular. For Regularity, is a Similitude continued. Since therefore all kinds of Atoms are divers only by their Size and Figure; if the self same Size and Figure were not common to a certain number of Atoms, they could not be said to be of any one kind: and consequently, if there were no Similitude of Atoms, there could be no Distinction of Principles.  
9 Hence also, these two Modes of Atoms, viz. their Size and Figure, are the true, and only original Qualities of Atoms. That is, an Atom is such or such, because it is of such a certain Size and Figure.  
10. Lastly, As these two Modes, taken severally, are the Qualities of an Atom: so considered together, they are its Form. A substantial Form of a Body, being an unintelligible thing. I say of a Body; for although the Rational Soul be a substantial Form, yet is it the Form of a Man, and not of a Body. For the Form of a Body, we can conceive of no otherwise, then as of the Modification of a Body, or a Complexion of all the Modes of a Body. Which also agrees with that Definition of a Form, which amongst the Peripatetic Philosophers is well enough accepted, viz. Quod sit, Ratio ejus Essentiae, quae cuique Rei competit. Which Ratio, if it be referred to a Body, what is it but the Modification of that Body? Having thus proposed a Summary of my Thoughts about Principles; I shall next proceed to show what their Mixture is.   

SECT. III.  
AND first of all, from the Premises, we arrive at this Conclusion; sc. That the Formation and Transformation of all Bodies, can be nothing else, but the Mixture of Bodies. For all Principles are immutable; as we have above proved: and therefore not generable, formable, or transformable. And the Forms of Principles, being but their Modes, are also immutable. So that the whole Business of the Material World, is nothing else, but Mixture.  
Again, as Nature worketh every where only by Mixture; so is this Mixture every where but one thing, and can be but one. For whether it be the Mixture of great Bodies, or of small; of Compounds, or of Atoms; it is every where Mixture, and the Mixture of Bodies. Wherefore, Mixture is either an intelligible Affection of all Bodies, or of none; which latter, no man will say. As many ways, therefore, as we can see, or conceive the Mixture of any gross Bodies, which we hold in our hand; so many ways, we may, of the subtlest Mixtures which Nature maketh, or of Atoms themselves; and no other ways.  
Now all the ways we can distinguish Mixture by, are in general these two; either in respect of the Bodies Mixed, or else of the Modes of the Mixture itself.  
In respect of the Bodies Mixed, Mixture is distinguished also two ways; viz. by Conjugation, and by Proportion.  
By Conjugation, I mean, a Certain Mixture of some such Principles, and not of others. Which is threefold.  
First, As to Number: as when one Body may be compounded of two Principles, another of three, a third of four, a fourth of five, and so on.  
Secondly, As to Kind: where, though there be a conjunction of the same Number, yet not of the same Kind.  
Thirdly, When they differ from one another both in Number and Kind.  
So many ways the Principles of Bodies may be conceived to be Conjugated; and therefore are: for here, that which may be, is. The Consequence is clear. For first, Nature hath various Materials wherewith to make these Mixtures; as we have showed. Secondly, By these Mixtures she may, and without the concurrence of any imaginary Forms, must produce all the varieties in the material world; as likewise hath been said. Wherefore, since all imaginable Mixtures may be made, and that to some purpose; if they should not be so, Nature would be Imperfect: because we ourselves can think, how she might put her Materials to further use, than so she would do.  
To think, therefore, that all kinds of Principles, or all Elements go to make up every Compounded Body; is a conceit, no more to be credited, than one that should tell us, all kind of Wheels and other parts of a Watch, were put into a Clock; or that there were no other Materials wherewith to build an House, then for a Tent or a Ship. For why should Nature, the great Artificer by which all perfect Works are made, be feigned to cram and ram all things into one, which we ourselves look upon as absurd?  
Secondly, The Mixture of Principles is diversified, as by Conjugation, so also by Proportion. That is, by the divers Quantities, of the several Principles or Parts mixed together.  
As if the quantity of one, were as five to ten; of a second, as five to fifteen; of a third, as five to twenty, etc.  
Or if that of one, be as five to six; of a second, as six to seven; of a third, as seven to eight. By which, and by other Proportions, Mixture may be varied innumerable ways.  
Again, As Mixture is varied with respect to the Bodies Mixed; so likewise in respect of the Mixture itself, which I call the Location of Principles, or the Modes of their Conjunction. Which may be various, as well as their Conjugation and Proportion. Yet are they all reduceable unto two general Modes: all Bodies, and therefore all Principles, being Mixed, either by Mediation, or by Contact.  
Now all Contact, whether of Compounds, or of Atoms, can be no other way, than such as is answerable to their Figures. Whereof, therefore, we can conceive but three general ways, viz.  
First, By Contact in a Point, or some smaller part: as when two Atoms meet, which are globular or otherwise gibbose.  
Secondly, By Contact in a Plain: as in the conjunction of the sides of Triangular or Quadrangular Atoms, or otherwise flat.  
Thirdly, By Contact in a Concave: as when one Atom is admitted into the Concave or hole of another; as a Spigot is into a Faucet.  
The first may be called, Apposition; the second, Application; the third, Reception or Intrusion.  
In the two last ways, Atoms may be joined by Mediation; but best of all the last. As when the two extremes of one Atom are received into the Concaves or the holes of two others.  
And these are all the general ways, whereby we can conceive Bodies to be Mixed together; sc. by their various Conjugation, Proportion, and Location.  
So that the Composition of Atoms, in Bodies; is like that of Letters, in Words. What a Thunderclap would such a Word be, as wherein all the four and twenty Letters were packed up? One therefore is compounded of more, another of fewer; this of some, and that of others: and both the Conjugation, Proportion, and Location of Letters is varied in every Word: whereby, we have many thousands of differing Words, without any alteration at all, in the Letters themselves; and might have ten times as many more. In like manner, therefore, or in the self same analogous' way, as the Letters of the Alphabet, are the Principles of Words; so Principles, are the Alphabet of Things.  
What we have said of Principles; and of Mixture as consequent thereupon; may be a foundation for an intelligible account, of the Nature and Cause of most of the Intrinsic Properties, and Qualities of Bodies: as of Gravity, Levity, Fixity, Fluidity, Angularity, Roundness, Heat, Cold, Blackness, Whiteness, Sourness, Sweetness, Fragrancy, Fetidness, and very many more. I say an intelligible account; sc. such as is grounded upon the Notions of Sense, and made out Mechanically. But the exemplification hereof, being too large a field for this, or any one Lecture, I shall, before I come to the Causes of Mixture, only deduce from the Premises, these following Corollaries.  
1. First, That there is no alteration of Principles or of Elements, in the most perfect Mixture of Bodies. It cannot be; for Principles are Immutable, as we have said. And if it could be, yet it needeth not to be: for they are also many, and compoundable infinite ways; as hath been showed. So that we have no need to perplex ourselves with any of those difficulties, that arise from the Doctrine of the Alteration of Elements. The ground of which conceit, is that, of there being but four Elements, and that all the Elements must needs be in every Body. And so men being puzzled, how from thence to make out the infinite variety of Bodies, they feigned them to be alterable, and altered, upon every perfect Mixture. Not considering, that if their four Elements be alterable; as few as they are, no fewer than three of them may be spared: for one Element, if alterable, may be made any.  
2. Hence, secondly, may be solved that great Dispute, Whether such as we call Lixivial Salts, are made by the fire?  
For first, No Principle is made by the fire: all Principles being unalterable; and therefore unmakeable.  
Secondly, We must therefore distinguish betwixt the Principle, and the Modification of a Principle; or its various Mixture with other Principles, whence it may receive a various denomination.  
Wherefore, a Lixivial Salt, qua Lixivial, is certainly made by the fire. But quatenus Salt, it is not: that Principle being extractable out of most Bodies; and by divers other ways, then by the fire. For whether you Calcine a body, or Ferment it, (after the manner showed by the diligent and curious Improver of Chemical Knowledge, Dr. Daniel Cox) or else putrify it under ground, or drown it in the Sea; it still yieldeth some kind of Salt. All which Salts are made, not by making the Saline Principle; but only by its being variously Mixed, upon those various ways of the Solution of Bodies, with other Principles: from which its various Mixture, it receives the various Denominations, of Marine, Nitrous, Volatile, or Lixivial.  
3. Hence, thirdly, the most perfect Mixture of Bodies, can go no higher than Contact. For all Principles are unalterable; and all Matter is impenetrable; as hath been said. In the most visible and lax Mixture, there is Contact; and in the most subtle and perfect, as in Generation itself, there is nothing more.  
4. Hence, fourthly, we easily understand, how divers of the same Principles, belonging both to Vegetables and many other Bodies, are also actually existent in the Body of Man. Because even in Generation, or Transmutation, the Principles which are translated from one body to another, as from a Vegetable to an Animal, are not in the least altered in themselves; but only their Mixture, that is, their Conjugation, Proportion, and Location, is varied.  
5. Hence also the difference of Mixture, arising from the difference of Contact, is intelligible; sc. as to those three degrees, Congregation, Union, and Concentration.  
Congregation, and Inconsistent Mixture, is when the several Atoms touch but in a Point, or smaller part. In which manner, I have divers arguments, inducing me to believe the Atoms of all Fluid Bodies, qua Fluid, do touch; and in no other.  
Union, is when they touch in a Plain. As in the Crystals and Shootings of all Salts, and other like Bodies. For if we pursue their divided, and subdivided parts, with our eye, as far as we can; they still terminate, on every side, in Plains. Wherefore, 'tis intelligible. That their very Atoms do also terminate, and therefore touch, in Plain.  
Concentration, is when two, or more Atoms touch by Reception and Intrusion of one into another: which is the closest, and firmest Mixture of all; as in any fixed, unodorable, or untastable body: the Atoms of such bodies, being not able to make any Smell or Taste, unless they were first dissolved; that is to say, unpinned one from another.  
6. Hence, sixthly, we understand, how in some cases, there seemeth to be a Penetration of Bodies; and in what sense it may be admitted: viz. if we will mean no more by Penetration, but Intrusion. For the Intrusion of one Atom into the Concave or hole of another, is a kind of Penetration; whereby they take up less room in the mixed Body, than they would do by any other way of Contact. As a naked knife and its sheath, take up almost double room, to what they do, when the knife is sheathed.  
Whence we may assign the reason, Why many Liquors being mixed; take up less room or space, than they did apart; as the very Ingenious M. Hook maketh it to appear by Experiment that they do. I say the plain reason hereof, or at least one reason, is the Intrusion of many of their Atoms one into another. Which yet is not a Penetration of Bodies strictly so called.  
7. If all that Nature maketh, be but Mixture; and all this Mixture be but Contact: 'tis then evident, That Natural and Artificial Mixture, are the same. And all those seeming subtleties whereby Philosophers have gone about to distinguish them; have been but so many Scarecrows, to affright Men from the Imitation of Nature.  
8. Lastly, Hence it follows, That Art itself may go far in doing what Nature doth. And who can say, how far? For we have nothing to Make; but only to Mix those Materials, which are already made to our hands. Even Nature herself, as hath been said, Maketh nothing new; but only Mixeth all things. So far, therefore, as we can govern Mixture, we may do what Nature doth.  
Which, that we may still the better understand; let us before, and in the next place, see the Causes of Mixture. For since Natural and Artificial Mixture are the same; the immediate Causes of both, are and must be the same.   

SECT. IV.  
NOW all the Causes of Mixture we can conceive of, must, I think, be reduced to these six in general; viz. Congruity, Weight, Compression, Solution, Digestion, and Agitation.  
1. Congruity, or aptitude and respondence betwixt the Sizes and Figures of parts to be mixed: whereby bodies may be truly called the Instrumental Causes of their own Mixture, As when a plain answers to a plain, a square to a square, a convex to a concave, or a less to a greater or an equal, etc. according to which Respondencies in the parts of Bodies, they are more or less easily mingleable.  
2. Weight; by means whereof, all Fluid Bodies, upon supposition of the Congruity of their parts, must unavoidably mingle  
3. Compression; which either by the Air, or any other body, added to Weight, must, in some degree, further Mixture. Because, that Weight itself is but Pression.  
For further proof of all the said Causes, I made this Experiment▪ Let Oil of Aniseeds, and Oil of Vitriol be put apart into the Receiver of an Air-Pump. And, having exhausted it of the Air, let the two said Oils be then affused one upon the other. Whereupon  
First, It is visible, that they here mix and coagulate together; that is, their parts are wedged and intruded one into another, without the usual compression of the Air; for that is exhausted: and therefore only, by the Congruity of their receiving and intruding parts; and by their Weight; by which alone they are so compressed, as to make that Intrusion.  
Secondly, It is also evident, That although they do Coagulate; yet not altogether so much, as when poured together in the same manner, and quantity, in the open Air. Wherefore, Compression, whether made by the Air, or any thing else, doth somewhat further the Mixture of Bodies, and the greater the Compression, the more.  
4. Solution; For all bodies mix best, in Forma fluida. And that for two reasons.  
First, Because the parts of a body are not then in a state of Union, but of Separation; and therefore, in a more capable state, for their Mixture and Union with the parts of another body.  
Secondly, Because than they are also in a state of Motion, more or less; and therefore, in a continual tendency towards Mixture; all Mixture being made by Motion.  
Wherefore, all Generations, and most perfect Mixtures in Nature, are made by Fluids'; whether Animal, Vegetable, or Mineral. Which is also agreeable to the Doctrine of the Honourable Mr. boil, in his excellent Treatise of the Nature and Virtues of Gems.  
And 'tis well known, That bodies are ordinarily- petrified, or Stones made, out of Water. That is, out of petrifying parts dissolved per minima in Water, as both their Menstruum and their Vehicle. Wherefore, if we will talk of making Gold; It must not be by the Philosopher's Stone, but by the Philosopher's Liquor.  
5. Digestion. For which there is the same reason, as for Mixture, by Solution. For  
First, All heat doth attenuate, that is, still further separate the parts of a body; and so render them more mingleable with the parts of another. And therefore  
Secondly, Doth also add more Motion to them, in order to their Mixture.  
6. Agitation. Which I am induced to believe a great and effectual means of Mixture, upon divers considerations. As  
First, That the making of Blood in the Bodies of Animals, and the mixing of the Chyle therewith, is very much promoted by the same means; sc. by the Agitation of the parts of the Blood and Chyle, in their continual Circulation.  
Again, From the making of Butter out of Milk, by the same means: whereby alone is made a separation of the oleous parts from the whey, and a mixture of them together.  
Moreover, From the great Effects of Digestion; well known to all that are conversant in Chemical Preparations. Which Digestion itself, is but a kind of insensible Agitation of the parts of digested bodies.  
'Tis also a known Experiment, That the readiest way to dissolve Sugar in Wine or other Liquor; is to give the Vessel a hasty turn, together with a smart knock, against any hard and steady body: whereby all the parts of the Sugar and Liquor, are put into a vehement Agitation, and so immediately mixed together.  
And I remember, that having (with intent to make Mr. Mathews' Pill) put some Oil of Turpentine and Salt of Tartar together in a bottle, and sent it up hither out of the Country; I found, that the continual Agitation upon the Road, for three or four days, had done more towards their Mixture; then a far greater time of Digestion alone had done before. And it is certain, That a vehement Agitation, especially if continued, or joined with Digestion; will accelerate the Mixture of some bodies, ten times more, than any bare Digestion alone; as may be proved by many Experiments.  
I will instance in this one. Let some Oil of Turpentine and good Spirit of Nitre be stopped up together in a bottle, and the bottle held to the fire, till the Liquors be a little heated, and begin to bubble. Then having removed it, and the Bubbles by degrees increasing more and more; the two Liquors will of themselves, at last fall into so impetuous an Ebullition, as to make a kind of explosion; sending forth a smoke for the space of almost two yards high. Whereupon, the parts of both the Liquors, being violently agitated, they are, in a great portion, incorporated into a thick Balsam in a moment: and that without any intense heat, as may be felt by the bottle. And thus much for the Causes of Mixture.   

SECT. V.  
HAVING enumerated the general Causes, we shall, lastly, inquire into the Power and Use of Mixture; or, into what it can Do and Teach. And I shall Instance in six particulars.  
First, To Render all Bodies Sociable, whatsoever they be.  
Secondly, To Make Artificial Bodies in Imitation of those of Nature's own production.  
Thirdly, To Make or Imitate the sensible Qualities of Body's; as Smells, and Tastes.  
Fourthly, To Make or Imitate their Faculties.  
Fifthly, It is a Key, to discover the Nature of Bodies.  
Sixthly, To discover their Use, and the Manner of their Medicinal Operation.  

Instance I.  
FIRST, To render all Bodies Sociable or Mingleable: as Water with Oil, Salt with Spirit, and the like. For Natural and Artificial Mixture, are the same; as we have before proved. If therefore Nature can do it, as we see in the Generation of bodies she doth; 'tis likewise in the Power of Art to do it.  
And for the doing of it, two general Rules result from the Premises, sc. The Application of Causes, and the Choice of Materials. As for the Causes, they are such as I have now instanced in. And for the Application of them, I shall give these two Rules.  
First, That we tread in Nature's steps as near as we can; not only in the application of such a Cause, as may be most proper for such a Mixture; but also in allowing it sufficient time for its effect. For so we see Nature herself, for her more perfect Mixtures, usually doth. She maketh not a Flower, or an Apple, a Horse, or a Man, as it were in a moment; but all things by degrees; and for her more perfect and elaborate Mixtures, for the most part, she requireth more time. Because all such Mixtures are made and carried on per minima; and therefore require a greater time for the completing of them.  
A second Rule is, Not only to make a due Application of the Causes; but sometimes to Accumulate them. By which means, we may not only Imitate Nature, but in some cases go beyond her. For as by adding a Graft or Bud to the Stock, we may produce Fruit sooner, and sometimes better, than Nature by the Stock alone would do: So here, by accumulating the Causes of Mixture; that is, by joining three, or four, or more together; or by applying more in some cases, where Nature applieth fewer; we may be able to make, if not a more perfect, yet a far more speedy Mixture, than Nature doth. As by joining Compression, Heat, and violent Agitation, and so continuing them all together, by some means contrived for the purpose, for the space of a week, or month, or longer, without cessation. Which may probably produce, not only strange, but useful effects, in the Solution of some, and the Mixture of other Bodies. And may serve to mix such Bodies, as through the small number of their congruous parts, are hardly mingleable any other way. Agitation being, as carrying the key to and fro, till it hit the lock; or within the lock, till it hit the wards.  
Secondly, For the Choice of Materials, if they are not immediately, that is, of themselves, mingleable; we are then to turn one species of Mixture into a Rule; which is, To mix them by mediation of some third, whether more simple or compounded body, which may be congruous in part to them both: as sulphurous Salts are to Water and Oil; and are for that reason mingleable with either of them.  
Or, By any two congruous Bodies, which are also, in part, congruous to two others: and other like ways. Whereby the parts of Bodies, though never so heterogeneous, may yet be all bound and locked up together. Even as twenty keys may be united, only by uniting the two Rings whereon they hang.  
The consideration of these things, have put me upon making several Experiments, for the Mingling of heterogeneous Bodies. I shall give two Examples of trial; the one upon fluid, the other upon consistent, Bodies.  
For the first, I took Oil of Aniseeds, and pouring it upon another Body; I so ordered it, that it was thereby turned into a perfect milk-white Balsam, or Butter. By which means the said Oil became mingleable with any other Liquor, Oil, Wine, or Water; easily, and instantaneously dissolving therein, in the form of a Milk. And note, That this is done, without the least alteration of the smell, taste, nature or operation of the said Oil.  
By somewhat the like means, not only Oil of Aniseeds, but any other stillatitious Oil, may be transformed into a perfect milk white Butter; and in like manner be mingled with Water or any other Liquor. Which is of various use in Medicine; and what I find oftentimes very convenient and advantageous to be done.  
Again, Not only fluid but consistent bodies, which of themselves will mix only with Oil; by due mixture with other bodies, maybe rendered easily dissoluble in Water; as may Rosin, and all resinous and friable Gums. As also Wax: and this without changing much of their Colour, Taste or Smell. Whereof likewise, whatsoever others may do, the Physician may make a manifold Use.   

Instance II.  
BY Mixture also, we may be taught to Imitate the Productions of Nature. As to which, from what we have before said of Mixture, we may conclude; That there is no generation of Bodies unorganical, but what is in the power of Mixture to imitate. As of Animals, to Imitate Blood, Fat, Chyle, spital, Phlegm, Bile, etc. Of Vegetables, to Imitate a Milk, Mucilage, Rosin, Gum, or Salt. Of Minerals, to Imitate Vitriol, Allom, and other Salts; as also Metals, and the like.  
I do not say, I can do all this: but if upon good premises we may conclude this may be done; it is one step to the doing of it. But I will also give an Instance of somewhat that may be done in every kind. And  
1. First, For the Imitation of an animal body, I will instance in Fat. Which may be made thus; Take Oil Olive, and power it upon high Spirit of Nitre. Then digest them for some days. By degrees, the Oil becomes of the colour of Marrow; and at last, is congealed, or hardened into a white Fat or Butter, which dissolveth only by the fire, as that of Animals.  
In converting Oil thus into Fat, it is to be noted, That it hardens most upon the exhalation of some of the more Sulphureous parts of the Spirit of Nitre. Which I effected, well enough for my purpose, by unstopping the glass after some time of digestion; and so suffering the Oil to dissolve and thicken divers times by successive heat and cold.  
Hence, The true Congealing Principle, is a Spirit of Nitre separated from its Sulphur. For the better doing whereof, the Air is a most commodious Menstruum to the said Spirit of Nitre.  
Whence also, if we could procure such a Spirit of Nitre, we might congeal Water in the midst of Summer. We might also refrigerate Rooms herewith artificially. And might Imitate all frosty Meteors. For the making of Fat, is but the Durable Congelation of Oil▪ which may be done without frost, as I have showed how.  
Hence also it appears, That Animal Fat itself, is but the Curdling of the Oily parts of the Blood; either by some of its own Saline parts; or by the Nitrous parts of the Air mingled therewith.  
Hence likewise it is, That some Animals, as Coneys, and Fieldfares, grow fatter in frosty weather: the oily parts of the blood, being then more than ordinarily coagulated with a greater abundance of nitrous parts received from the Air into their bodies.  
For the same reason it is, That the Fat of Land-Animals is hard; whereas that of Fish is very soft, and in a great part runs to Oil, sc. Because the Water, wherein they live, and which they have instead of breath, hath but very few nitrous parts in it, in comparison of what the Air hath.  
2. For the Imitation of a Vegetable Body, I will give three Instances; In Rosin, Gum, and a Lixivial Salt. The first may be made thus; Take good Oil of Vitriol, and drop it upon Oil of Aniseeds; and they will forthwith incorporate together; and by degrees, will harden into a perfect Rosin; with the general and defining Properties of a truly Natural Resinous Gum. Being not in the least dissoluble in Water; or at least, not any more, than any natural Rosin or Gum: yet very easily by fire: as also highly inflammable: and exceeding friable.  
Although this artificial rosin, be the result of two Liquors, both which very strongly affect the Sense: yet being well washed from the unincorporated parts, (which is to be done with some care) it hath scarce any Taste or Smell.  
The Concentration of these two Liquors, is likewise so universal; that the Rosin is not made by Precipitation, but almost a total Combination of the said Liquors; and that with scarce so much, as any visible fumes.  
Again, Having taken a certain Powder and a Saline Liquor, and mixed them together in a bottle, and so digested them for some time; the Powder was at last transmuted to a perfect Oily Gum; which will also dissolve either in Oil, or in Water; in the self same manner, as Galbanum, Ammoniac, and the like will do.  
And Lastly, A Lixivial Salt may be imitated thus; Take Nitre, Oil of Vitriol and high Spirit of Wine, of each a like quantity. Of these three Bodies, not any two being put together; that is to say, neither the Nitre with the Oil, nor the Oil with the Spirit, nor the Nitre with the Spirit; will make the least ebullition: yet all three mingled together, make a very conspicuous one. The Spirit of Wine being as the Sulphur; and so that, and the Nitre together, standing, as it were, in the stead of an Alkalizate, that is, a Sulphurous Salt, against the Oil of Vitriol. Divers other Experiments I can show of the like nature.  
3. In the last place, for the Imitation of a Mineral Body, I will instance in two, sc. Nitre and Marine Salt; if I may have leave to reckon them amongst Mineral Bodies. As for Nitre, by mixing of four Liquors together, and then setting them to shoot; I have obtained Crystals of true and perfect Salt; which have had much of a nitrous taste; and would be melted with a gentle heat, as Nitre is; and even as easily as Butter itself: I mean, not by the addition of any sort of Liquor, or any other body, to dissolve it; but only by the fire.  
And as for a Sea-Salt, that I might Imitate Nature for the making hereof, I considered, That the Salt so called, was nothing else but Animal and Vegetable Salt, freed from its true Spirit and Sulphur, and some Saline particles, specifically Animal or Vegetable, together with them. For both Animal and Vegetable bodies being continually carried by all Rivers into the Sea; and many likewise by Shipwreck, and divers other ways, immersed therein: they are at last corrupted, that is, their Compounding parts are opened and resolved. Yet the Resolution being in the Water, is not made precipitately, as it is in the Air; but by degrees, and very gently. Whence the Sulphurous, and other more Volatile parts, in their avolation, make not so much haste, as to carry the more fixed Saline parts along with them; but leaveth them behind in the Water, which imbibeth them, as their proper Menstruum.  
And the Imitation of Nature herein, may be performed thus; Put as much of a Lixivial Salt as you please, into a wide mouthed bottle, and with fair Water make a strong Solution of it; so as some part thereof may remain unresolved at the bottom of the bottle. Let the bottle stand thus for the space of about half or three quarters of a year, all the time unstopped. In which time, many of the Sulphurous and other more Volatile parts gradually flying away; the top of the unresolved Salt will be incrustate, or as it were frosted over, with many small and hard Concretions, which for their nature, are become a true Sea-Salt. Whereof there is a double proof; First, In that most of the said Concretions are of a Cubical, or very like Figure. Especially on their upper parts; because having a fixed body for their basis, their under parts, therefore, contiguous thereto, are less regular. Whereas the parts of Salt in the Sea, being environed on all sides with a fluid; their Figure is therefore on all sides regular. Secondly, In that a strong Acid Spirit or Oil being poured upon a full bodied Solution hereof; yet it maketh herewith no Ebullition; which is also the property of Sea-Salt. And thus much for the more general Imitation of Bodies.   

Instance III.  
FROM the aforesaid Premises, and by the aforesaid Means, there is no doubt to be made, but that also the other sensible Qualities of Bodies may be Imitated, as their Odours and Tastes. And that not only the general ones, as Fragrant, or Astringent: but also those which are specifical and proper to such a species of Bodies. Thus, for example, by mixing several Bodies together, in a due proportion, I have Imitated the Smells of divers Vegetables; as of Tansy, of Lignum Rhodium, and others. And I conclude it feasable, To Imitate the Taste or Smell of Musk, or Ambergris, or any other body in the world.   

Instance IU.  
HENCE also we may be Taught, How to Imitate the Faculties, as well as other Qualities of Bodies. The reason is, because even these have no dependence upon any substantial Form; as in the first Part of my last Book of the Anatomy of Vegetables, I think, I have, in a few lines, clearly made out: but are the mere result of Mixture; effected by the same Causes, whether in Nature or Art; as also in the premises of this Discourse hath been showed.   

Instance V.  
FROM whence, again, it is likewise a Key to Discover the Nature of Bodies. For how far soever we can attain to Mingle, or to Make them, we may also know what they are.  
For Bodies are mingleable, either of themselves, or by some third. As to those which mingle of themselves, we may certainly conclude, That there is a congruity betwixt them, in some respect or other. So upon various trials I find, that Essential Oils do more easily imbibe an Acid, than an Alkaly. Whence it is evident, That there is some congruity and similitude betwixt Essential Oils, and an Acid, which there is not betwixt the said Oils and an Alkaly.  
As to those that mingle only by some third; we may also certainly conclude, That though the two extremes are unlike; yet that they have both of them a similitude to or congruity with that third, by which they are united.  
Moreover, We may make a Judgement from the Manner or Degree of Mixture. Thus the Acid Spirit of Nitre, as is said, will coagulate oil-olive, and render it consistent. Whence it might be thought, That any other strong Acid will do the like; and that therefore, there is no great difference in the Nature of the said Acid Liquors. But the contrary hereunto, is proved by Experiment. For having digested the same Oil, in the same manner, and for a much longer time, with strong Oil of Sulphur; although it thence acquired some change of Colour, yet not any Consistence.  
Again, Because the said Spirit of Nitre coagulates oil-olive; it might be expected, it should have the same effect, upon Oil of Aniseeds; or, at least, that if other Acids will coagulate Oil of Aniseeds, that this should do it best. But Experiment proveth the contrary. For of all I have tried, Oil of Vitriol is the only Acid that doth it instantaneously. Oil of Sulphur, if very strong, will do it; but not so soon, nor so much. Aqua fortis, and Spirit of Salt, for the present, do not at all touch it. And Spirit of Nitre itself will not coagulate it, under eight or ten hours at least.   

Instance VI.  
LASTLY, and consequently, It is a Key, To Discover the Medicinal Use and Operation of Bodies. Thus, for example, by the Imitation of Rosins and Resinous Gums, we certainly know what all of them are, and when, and wherefore to be used. For what are Mastic, Frankincense, Olibanum, Benzoin, and other like Rosins, or Resinous Gums, for their principal and predominant parts, that is, qua Rosins; but Bodies resulting from Natural, in like manner, as I have showed, they may be made to result, from Artificial Mixture? That is to say, the Oleous, and Acid parts of Vegetables, being both affused and mingled together, per minima, in some one Vessel of a Plant, they thus incorporate into one consistent and friable body, which we call Rosin.  
Now from hence it is, that the said Rosins, and Resinous Gums; as also Amber and Sulphur for the same reasons; are of so great and effectual Use against most thin and salted Rheums; sc. as they are Acido-oleous Bodies. For by their Acid parts, which in all these Bodies are exceeding copious, they mortify and refract those salt ones which feed the Rheum. And by their oleous parts, the same salt ones are also Imbibed. Whence, they are all, in some degree, incorporated together; that is, the Rheum is thickened: which is the desired effect.  
Whereas, on the contrary, if the Cough proceed not from a thin and especially a salt Rheum, but from a Viscous Phlegm; the use of many other Bodies, which are also more oleous, and abound not so much with an Acid as these do, especially some of them, is more proper: such as these, in this case, proving sometimes not only ineffectual, but prejudicial. Since the very Cause of the said Viscousness of Phlegm, is chiefly some great Acidity in the Blood, or in some other part; as may be proved by divers arguments.  
Many more Instances might be hereunto subjoined: and may hereafter be offered to the acceptance of such, who are inquisitive into matters of this Nature. If I shall not herein anticipate, or reiterate the Thoughts and Observations, of those two accurate and Learned Persons Dr. Willis, and Dr. Walter Needham, as to what the one hath already published, and both have put us in expectation of. But the Instances already given, are sufficient to evidence what I have said. And, I hope, this present Discourse to prove, in some measure, thus much; That Experiment, and the Common Notions of Sense are prolific; and that nothing is barren, but fancy and imagination.    
FINIS.